This application claims the priority of German patent document 199 26 608.5, filed Jun. 11, 1999, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a chemical reactor for a fuel cell system.
A device for methanol reformation is known from DE 195 26 886 C1, in which the effective length and/or the effective entrance cross section on the input side of a reaction chamber section for a high methanol reaction can be adjusted so that an essentially constant residence time of the gas mixture to be reformed is obtained in the reactor chamber section.
The load spread of the reactor system is thus improved and influenced less by the otherwise strong variation in the educt residence time. In the same way, undesired back reactions caused by residence times that are too long are avoided. Nevertheless, the behavior of the system is unsatisfactory under cold start conditions, since the reformation reactors usually employed have unavoidably high thermal capacities.
The goal of the present invention is to provide a chemical reactor for a fuel cell system that has improved cold start behavior.
This goal is achieved in a reformation reactor according to the present invention. The reactor according to the present invention has a reaction chamber with (1) at least one reaction partial chamber of a first type, and (2) at least one reaction partial chamber of a second type. Only the at least one reaction partial chamber of the first type is open when the system is started. The reaction partial chamber of the first type is designed so that it warms up more rapidly than a reaction chamber of the second type under the same operating conditions.
It is advisable to provide more than one reaction partial chamber of the first type. It is especially advantageous to locate the reaction partial chambers of the first type as homogeneously as possible inside the reaction chamber. The result is that the reaction chamber warms up rapidly, especially in the cold start phase, and homogeneously over its length. A temperature gradient is avoided between the input and the output of the reaction chamber.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.